Compressor



H. C. JOHANSEN.

Patented Jan. 17, 1922.

OlllllbAlllJ UNITED STATES PATENT OFFICE.

BARRY C. JOHANSEN, OF CHICAGO, ILLINOIS, ASSIGNOR TO SULLIVAN MACHINERY COMPANY, A CORPORATION OF MASSACHUSETTS.

comrnassoa.

Application filed May 7, 1919.

To all whom it may concern:

Be it known that I, HARRY C. JOHANSEN, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Compressors, of which the following is a full, clear, and exact specification.

This invention relates to compressors and more especially to a compressor unloading means.

One object of the present invention is to provide an improved unloading means and more especially an improved means of the type shown in application Number 878,187 filed Dec. 19, 1914. Another object of the present invention is to provide a very compact and efficient unloading means which may readily be attached to any compressor. Still another object of the present invention is to provide an unloading mechanism which may be attached to one of the higher stages of a multi-stage compressor to prevent excessive temperatures in this stage when the inlet to one of the lower stages is closed or partially closed. These and other objects and advantages of my improved construction will, however, hereinafter more fully appear.

In the accompanying drawings I have shown one embodiment which my invention may assume in practice.

In these drawings,

Fig. 1 is a side elevation of a compressor provided with my improved unloading means.

Fig. 2 is a detail view of the high pressure 0 linder thereof, parts being shown in sectlon to facilitate illustration.

Fig. 3 is a longitudinal sectional view of my improved unloading mechanism.

Fi 4 is a transverse sectional view thereof su stantially on the line 4-4 Fig.3.

Referring to the drawing and to the embodiment of my invention which I have selected for illustrative purposes, I have there shown a compressor of the angle compound type havin a horizontal low pressure double acting cy inder 1, a high pressure double acting vertical cylinder 2, and driving mechanism for the pistons reciprocable in these cylinders whereby the two stages Specification of Letters Patent.

Patented Jan. 1'7, 1922.

Serial No. 295,482.

are operated from a single crank shaft 3.

The intake to the low pressure cylinder 1 is through inlet pipe 4 past an automatically operated unloading means 5 such as is commonly used on compressors to unload the compressor when the pressure in a supply pipe or receiver rises above the normal operating pressure. The air or other fluid under partial compression passes from the first stage cylinder 1 through an intercooler 6 to the high stage cylinder 2 and from thereafter final compression through a pipe 7 to the main or receiver.

When the pressure in the receiver or pipe main rises above the normal operating pressure, the unloading means 5 is operated, preferably automatically, in a well known manner to close the inlet to the low pressure cylinder 1 to prevent the intake of air through the inlet and hence the operation of the compressor to force more air into the main or receiver. However, due to leakage or other causes a certain amount of air Wlll pass by this cylinder into the intercooler and will be compressed in the high pressure cylinder 2 from atmospheric ressure or sometimes from below atmosp eric pressure to the final pressure. This results in a ver high temperature in the high pressure cy inder 2, often sufficient to explode mixtures of gas and air which may be formed in this cylinder from the vaporization of the lubri eating oil used in the compressor, with a re sultant damage to the latter. To obviate this, I mount on the high compressor cylinder 2 an improved unloading mechanism which prevents the operation of the high pressure cylinder 2 in the manner just stated when the inlet 4 of the low pressure stage is closed.

For this purpose I preferably use a single unloading mechanism 8 and preferably connect this mechanism directly to the opposite ends of the cylinder 2 as y pipes or conduits 9. In the form of my invention shown herein, I provide in the unloading means 8 a plurality of similar, aligned valve chambers 10 in which are preferably inserted valve bushings 11 which are preferably held in position against flanges 12 formed on the valve casing by valve plugs 13, these bushings having adjacent one of their ends ports 14 which the fluid is ejected into the pipe 7.

which communicate with passageways 15 preferabl formed in the walls 0 the valve casing. hese valve bushings are preferably held in a fixed predetermined position in the valve chambers by screws 16 so that the ports 14 always register with the corresponding ports 15 inthe casing. The inner ends of the valve bushings are preferably formed conical to provide an air tight fit with the flanges 12, these ends of the bushings also serving as stops to limit the rearward movement of valve heads 1?. These valve heads are carried and guided by hollow valve stems or skirts 18 which slide in the bushings 11, the rear surfaces of these valves being referably always in communication with t e ports 14 and 15. The valve heads are held against suitable valve seats 19 by light springs 20 having preferably sutlicient strength to just normally retain these valve heads against cooperating seats 19.

Communicatin also with the passageways 15 are annu, ar channels 21 which permit a free flow of fluid from the passage ways 15 to a chamber 22, herein shown as formed between the valve heads 17, when the valves are open. sageways'15 through the recesses 21 and past the valve seats 19 and through the chamber 22 permits an exhausting of any pressure which may accumulate in the ends of the cylinders through a lateral ort 23 which may, if desired, communicate irectly to the atmosphere through an adjacent port 24 or the exhaust fluid may be conducted to any desired point as by means of pipe, not shown, which may be threaded into a suitable connection 25. However, I preferably provide a small check valve 26 normally eld in position by a light spring 27 to close thelport 23, this check valve serving to prevent an inrush from the opposite direction through these ports and passageways and through the pipes 9 to the end of the c linder not under compression when the piston would normally be drawing fluid into this end of the cylinder.

In the operation of this improved mechanism, the pressure in the pipes 9 will alternately rise and fall according to the conditions in the ends of the cylinder to which each of these pipes is in free communication. When the inlet 4 of the low pressure cylinder is opened, and fluid is being compressed in the low pressure cylinder 1, the pressure variance in the pipes or conduits 9 will be between a lower imit constituting the pressure of the fluid in the intercooler 6 and a higher limit which is the pressure under Under these conditions, the valves in the unloading mechanism will remain closed. However, if the inlet 4 is closed and a partial vacuum is thereby formed in the inter- The flow from the pas.

cooler ti and the adjoining pipes, a partial vacuum will also be formed on the inlet side of the cylinder 2, that is, the side under suction, and this partial vacuum will also exist in one of the pipes 9, and the corresponding ports 14 and 15, and valve cham-- ber 10 ermitting the atmospheric pressure in the c amber 22 to force one of the valves from its seat and thus establish communication between the opposite end of the cylinder which is under compression through the other pipe 9 and passageway 15 to the chamber 22 from which this compressed fluid is exhausted past the valve 26. As the piston in the cylinder 2 reciprocates, the two valves in the valve mechanism 8 will be alternately opened and closed to alternately exhaust the fluid on the compression side of the piston to the atmosphere.

It will thus be seen that I have provided a very simple unloading mechanism which is automatically operated to relieve the pres sure on the compression side of the piston in the compressor cylinder to prevent the overheating of the gases in this cylinder. It will further be noted that my improved unloading means may be easily applied to any compressor'at a small initial cost and that the u keep of this unloading means will be vegzh' ht.

ie I have in this application specifically described one embodiment which my invention may assume in practice, it is to be understood that this form is used for illustrative purposes only and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What Iclaim as new and desire to secure by Letters Patent is:

1. An unloading mechanism for a compressor cylinder comprising means responsive directly to the pressure variations at one end of the cylinder to unload the other end thereof.

2. An unloading mechanism for a double acting com ressor cylinder comprising a plum ity 0 means each responsive directly to pressure variations at one end of the cylinder to unload the other end thereof.

3. An unloading mechanism for a compressor cylinder having a plurality of passages communicating with the ends thereof and adapted for connection with the atmosphere including a plurality of valves each of which controls one of said passages and whose opening is controlled by the pressure conditions in the other of said passages.

4. An unloading mechanism for a compressor cylinder comprising a casing, a plurality of valves therein, a connection with the atmosphere, and passages leadingone from each end of the cylinder to said casing and having atmospheric connection controlled by said their communication with the valves, each of said valves being governed as to opening by the pressure conditions in that one of said connections which it does not control.

5. An unloading mechanism for a compressor cylinder comprising a plurality of valves and a pluralit of passages each controlled by one of sai valves and adapted to vent an end of said cylinder, the closing of each of said valves and also the opening thereof being governed by pressure conditions in the passage which is controlled by the other of said valves.

6. An unloading mechanism for a compressor cylinder comprising a plurality of valves, and a plurality of passa es each communicating with one end of tie cylinder and each controlled by one of said valves and communicating with the other, each of said valves being adapted to be controlled as to closing by the pressure conditions in the passage wh'ich it does not control and as to opening also by theconditions in said passa e.

7. n unloading mechanism for a compressor cylinder comprising a plurality of valves, means for normally maintaining said valves closed, and a lurality of passages each communicating with one end of the cylinder and each controlled by one of said valves and communicating with the other, each of said valves being adapted to be controlled as to closing by the pressure conditions in the passage which it does not control and as to opening also by the conditions in said passage.

8. In 'a compressor unloading mechanism, a valve casing provided with a plurality of inlet ports and an exhaust port, valves controlling each of said inlet ports, passa es connecting said orts with the ends 0 a compressor c lin er, and means cooperating with said va v-es and controlled by ressure conditions in said passages for loading said compressor.

9. In acompressor controlling mechanism, a valve casing having a pluralit of inlet ports adapted to communicate wit the ends of a compressor cylinder, an exhaust port, and valves one controlling each of said inlet ports and controlled b pressure conditions in said passages to unIoad said compressor.

10. In a compressor controlling mechanism. a valve casing having a plurality of inlet ports adapted to communicate with the ends of a compressor cylinder, an ex haust port, valves one controlling each of said inlet ports and controlled by pressure conditions in said passages to unload said compressor. and a normally closed valve controlling said exhaust port.

ll. The combination of a compressor cvlinder and'its piston. with means for shutting off the inlet. supply of air thereto, and an unloading means responsive to a rela tively low pressure in one end of the cylinder to discharge a higher pressure from the opposite end thereof.

12. I1; a compressor unloadi mechanism, a valve mechanism, a plurality of inlets thereto, an outlet therefrom, and a valve member operatedby a relatively low pressure in one of said inlets to place another of said inlets in communication with said outlet.

13. In a valve mechanism, a casing, a plurality of valves therein, fluid conducting means having communication with said valves one of which is opened by a variation in pressure in said conducting means, an means for opening another of said valves to relieve a pressure in said conducting means.

14. In a valve, a plurality of symmetrically disposed valve chambers and an intermediate chamber, a plurality of symmetrically disposed conduits communicating with said valve chambers and communicable with said intermediate chamber, and means for closing communication between said crinduits and said intermediate chamber, each of said closing means bein controlled by pressure variations in one 0 said conduits.

15. In an unloading mechanism, a plurality of valve chambers, seats therein, closing means therefor, and a plurality of separate fluid conducting means, each of which is in communication with one of said valve chambers and may be placed in communication with another of said valve chambers by said closing means.

16. In an unloading mechanism, a plurality of valve chambers, seats therein, closing means therefor, and a plurality of se arate fluid conducting means, each of which is in communication with one of said valvechambers and may be placed in communication with another of said valve chambers by said closing means, one of said closing means being operable upon a fall in pressure in one of said conductin means to permit a fluid flow through anot er of said conducting means.

17. An unloading mechanism for a compressor cylinder comp-rising a valve having an area acted on by pressure variations at one end of the cylinder, said valve being held closed by the pressure to which it is exposed during one stroke and opened upon reduction of pressure on the next stroke, and a passage leading to the other end of the cylinder and communicable with the atmosphere, said valve being operative to control the communication between the said passage and the atmosphere.

18. An unloading mechanism for a compressor cylinder comprising a plurality of valves each subject to the iremure at both ends of the oompremor cylinder. and each controlled by pressure variations at one end dso from the other end.

5 "elves each subject to pressure from th ends of the cylinder and to substantially atmospheric pressure, and each controlled by the latter and by pressure variations in one end of said compressor: cylinder to control the discharge of air from the other.1 end of said compressor cylinder.

In testimony whereof I afiix my signature.

HARRY o. JOHANSEN.

said cylinder to permit discharge of air 19. An unloading mechanism for a, comessor cylinder comprising a pluralit of 

